Toroidal two-cycle engine

ABSTRACT

A toroidal two-cycle engine in which two opposed pairs of pistons oscillate in opposition in four toroidal cylinders, dual power strokes occuring at each reversal of piston motion. An intake manifold connecting all cylinders is charged with combustible mixture through a uniflow scavenging system, utilizing the motion of the pistons in both directions. The engine is of simple construction and the inertia of the moving parts is equal and opposite about a common axis, so that vibration and stress are minimized. Functional parts of the engine are readily accessible and the structure is easily dismantled for servicing.

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PATENTEU- M1931 |911 SHEET 1 UF 2 IOO INVENTOR.

ATTORNEY INVENTOR.

SHEET 2 0F RBERT C. MOWRY @aa/fm l ATTORNEY los PATENED Auml mi TOROIDALTWO-CYCLE ENGINE BACKGROUND OF THE INVENTION Various types of toroidalengines with oscillating pistons have been developed with complexcoupling and drive mechanisms, usually external, which make the enginesbulky and intricate. Fuel and exhaust flow is usually controlled bysynchronized valve means, again requiring complex operating mechanism.

SUMMARY OF THE INVENTION The engine described herein has two opposedypairs of pistons oscillating about a common axis in` four toroidalcylinders, synchronization being maintained by coupling means completelycontained within theV engine. Dual power strokes occur at eachA limit ofpiston' motion, the inertia of the moving parts being equal andopposite, so that vibrationand stress are minimized. Motion of thepistonsy in both directions through scavenging chambersbetweenthecylind'ers, charges an intake manifoldwith combustible'mixturethrough simple nonretum valves, withfa unitlow type action. Nomechanically coupled or synchronized valves are necessary in-the engine.Common intake and exhaustmanifolds areincorporated in end? housings,which also provide bearings for dual output shafts. The only movingparts are the pistons and their coupling means, the engine structurebeing very simple.

An object of this invention, therefore, is to provide a'n`ew andimproved toroidal two-cycle engine having internallycoupled oscillatingpistons which have'power strokes at each limit of piston motion, inopposed and balanced relation.

Another object of this invention is to provide a toroidal twocycleengine having a unitlow scavenging 'and 'intake chargingy action,without the need-for: mechanicallyv driven or timed valves.

A further objectof'this invention is to provide a toroidal two-cycleengine of simple construction with very few' moving parts, and which iseasily serviced.'

Other objects and manyfadvantagesof -this inventionwill' becomemoreapparent` upon al readingl of theA following detailed descriptionand anexamination of the drawings, wherein like reference numeralsrdesignate like parts throughout and in which: f

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OFTHEPREFERRED EMBODIMENTThe engine is generally a flat cylindrical cylinder unit havingV fourcylinder blocks 10, l2, 14 andlequally spaced around a central sleeve1,8. Each cylinder block'is a sector of a ring` element of rectangularcross section and has a toroidal cylinder bore 20, the four bores beingin common toroidal alignment. On opposite ends of the cylinder blockassembly are flat circular separator plates 22 'and 24 and fixed overthe separator plates are end covers 26 and 28,-respectively. Each Ashaft 46 extends axially through the unit and is journaled at one end inend cover 28, the other end having a bearing in a concentric tubularshaft 48, which in turn is journaled in end cover 26. Fixed to shaft 46is a hub 50 having a pair of diametrically opposed arms 52 which extendthrough slots 54 in sleeve 18. One arm 52 carries a scavenging vane 56which is a close sliding fit in chamber 36, the other arm carrying asimilar scavenging vane 58 which slides in chamber 40. Fixed on shaft 48is a hub 60 with a pair of diametrically opposed arms 62 extendingthrough slots 64 in sleeve i8, at the opposite end from slot 54. One arm62 carries a scavenging vane 66 which slides in chamber 38 and the otherarm carries a scavenging vane 68 which slides in chamber 42. For ease ofassembly, the hubs 50 and 60 are preferably split diametrically andsecured by screws or other retaining means. To reduce blowby betweenopposed chambers, wiper vanes 69 are held betweenthe split hub portions,as in FIG. 1, and swing with a close fit inside sleeve 18.

In operation the pairs of scavenging vanes swing in short arcs inopposite directions and must be synchronized by a suitable linkage suchask gears, a yoke or a hydraulic coupling. The simple arrangement showncomprises a bevel gear 70 fixed on shaft 46, an opposed bevel gear 72fixed on shaft 48 and one or more pinion gears 74 interconnecting thebevel gears. InFlG. 5', a pinion gear 74 is shown mounted on a stubshaft 76` secured in the cylinder block v10, buty any suitable bearingmay be used. Plain'bearings in the end covers are also indicated for theshafts'46 and 48, but it will be obvious that conventional ball orroller bearings could be incorporated.

For ease of manufacture and assembly, the pistons are each made in twoparts, each scavenging vane carrying a pair of end cover has aperipheral flange 30, and the-assembly is secured by capscrews 32, orthe-like, through the flanges and separator plates, into the cylinderblocks. The peripheral gaps between the cylinder blocks are closed bycover plates 34,`en

lclosing scavenging chambers 36, '38,k 40 and 42 Each cover plate 34 hasan inlet 44 opening substantially into the center of the respectivescavengingchamber.

pistons on opposite sides. Each scavenging vane has a bore 78 and issplit diametrically of the bore to provide a clamp portion 80, which issecured by cap screws 82 or the like. Two pistons are fitted into eachbore with their ends abutting and are secured by retaining rings 84inset into the pistons and the bore, as in FIG. 1. Scavenging vane 56thus carries a'piston 86 riding in the toroidal bore of cylinder block16, and an opposed piston 88 riding in cylinder block 10. Scavengingvane 66 vcarries a piston 90 riding in cylinder block 10 and an opposingpiston 92 riding'in cylinder block l2.` Scavenging vane S8carries'pistons 94'and 96 'riding in cylinder blocks l2 and 14,respectively, and scavenging vane 68 carries pistons 98 and 100, whichride in cylinder blocks 14 and 16, respectively.

At opposite ends of eachvscavenging chamber the separator plats 22and 24have. transfer ports 102 and 104 opening into annular intake manifoldpassages 106 and 108, respectively, in the end covers 26 vand 28.L Thetransfer ports are normally closed by reed valves 110, which open intothe manifold passages but prevent return flow. Other types of one-wayvalves may be equally suitable. At one end of each cylinder bore 20 areinlet ports 112 and 114 passing through the respective cylinder blockinto radial slots 116 and 118. In the separator plates 22 and 24 areinlet ports 120 and 122aligned with slots 116' 'and 118.', respectively,and opening into intake manifolds l06and 108."

The'end covers 26`and 28 have exhaust manifold passages 126'and 128,respectively, outside and concentric with the intake manifold passages106 land 108. At the other end of each cylinder borev 20 are exhaustports 130 and 132 passing through lthe respective cylinder block intoradialv slots 134 and 136.y Separator plates 22 and 24 have exhaustports 138 and 140, aligned with slots 134 and 136 and opening intoexhaust manifolds 126 and 128, respectively. End covers 26 and 28 haveexhaust outlets 142 suitably located around the exhaust manifolds, andan external manifold, not shown, may be used to connect the exhaustoutlets and conduct and muftle the exhaust if necessary.

Each cylinder block is provided with a spark plug 144, or other ignitionmeans, inset in the outer wall at the center of each cylinder bore 20.Conventional ignition circuitry may be used and timed in any well-knownmanner by coupling to either of shafts 46 and 48, or to some othermoving part with appropriatelyy timed action.

In the form shown the two shafts 46 and 48 have an opposed rotaryoscillating motion. For some purposes, such as pumping this drivingaction may be used directly, but mechanisms for converting oscillatoryto continuous rotary motion are well known. The engine is started by anysuitable means coupled to one or both ofthe shafts. A combustiblemixture is supplied to allv inlets 44 from a conventional source, suchas a carburetor. As the scavenging vanes oscillate from end to end oftheir respective chambers, combustible mixture in the chambers is driventhrough transfer ports 102 and 104 into the intake manifolds 106 and108. Reed valves 110 prevent backflow, so the intake manifolds are keptcharged with combustible mixture under pressure.

Starting from the position shown in FIG. 1, combustible mixture from theintake manifolds enters cylinder blocks and 14 through the exposed inletports. As the pistons 88 and 90 come together in cylinder block 10, andpistons 96 and 98 come together in cylinder block 14, the mixturebetween the approaching pistons is compressed. The intermediate positionof the pistons is shown in FIG 6, with the motion indicated bydirectional arrows on the approaching pairs of pistons. At the peak ofcompression, as in FIG. 7, the spark plugs fire and the resultantexplosion drives the pistons apart. When the cylinder ports becomeexposed, the incoming charge of mixture through the inlet ports drivesthe combustion products out through the exhaust ports into exhaustmanifolds 126 and 128. The explosion also drives pistons 92 and 94together in cylinder block l2, and pistons 86 and 100 together incylinder block 16, to repeat the action in those two cylinders. Thusdual, equal and opposite power strokes occur alternately in opposedpairs of cylinders. The scavenging vanes maintain a constant supply ofcombustible mixture to the intake manifolds, and the only valves neededare the reed valves 110, or their equivalents, which do not require anytiming mechanism. With the intake and exhaust ports at opposite ends ofeach cylinder, efficient uniflow scavenging and recharging occurs at themaximum separation of the pistons.

The moving parts are balanced about the axis of rotation and the inertiais equal andl opposite, resulting in a very smooth-running engine. Byproper weight distribution in the moving parts, the engine may bedesigned to have a particular stable oscillation frequency and run at aconstant speed for a specific purpose, such as for driving an ACgenerator or alternator. With few moving parts and no elaborate timingor synchronizing mechanism, the structure is simple and easy to service.The engine will operate ori a variety of fuels, with electrical ignitionmeans or using compression ignition, or a fuel injection system may beused with conventional injectors in place of the spark plugs and airsupplied to the intakes, thereby allowing an increase in operatingspeed.

Having described my invention, I now claim.

l. A toroidal two-cycle engine, comprising,

a cylinder unit with circumferentially spaced blocks having toroidalcylinder bores in common toroidal alignment,

said cylinder unit having enclosed scavenging chambers between saidcylinder blocks,

a pair of counterrotating shafts coaxialiy mounted in said cylinderunit,

a pair of opposed scavenging vanes fixed to one of said shafts andsliding in one opposite pair of said scavenging chambers,

a pair of opposed scavenging vanes fixed to the other of said shafts andsliding in the other opposite pair of said scavenging chambers,

pistons secured on and extending from opposite sides of each of saidscavenging vanes and sliding in said cylinder bores,

each of said cylinder bores having inlet ports at one end and outletports at the other end thereof,

an intake manifold communicating with all of said inlet ports,

each of said scavenging chambers having an inlet for con nection to asource of combustible mixture,

transfer ports from each of said scavenging chambers to said intakemanifold, with nonreturn valve means therein, and synchronizing meansinterconnecting said shafts to rotate equally in opposite directions.

2. An engine according to claim l, wherein said transfer ports are atopposite ends of each of said scavenging chambers.

3. An engine according to claim 1, wherein said pistons are in pairssecured in end to end abutting relation in said scavenging vanes.

4. An engine according to claim l, and including ignition means in eachof said cylinder bores.

5. An engine according to claim l, and including a separator plate fixedto at least one of said cylinder unit and enclosing the ends of saidscavenging chambers, said transfer ports extending through saidseparator plate.

6. An engine according to claim 5, wherein said valve means are mountedon said separator plate.

7. An engine according to claim 6, wherein said valve means comprisesresilient reed valves secured to said separator plate externally of thescavenging chambers and normally closing said transfer ports.

8. An engine according to claim 5, and including an end cover securedover said separator plate said intake manifold comprising an annularchannel in said end cover.

9. An engine according to claim 8, and including an annular exhaustmanifold in said end cover, communicating with said exhaust ports.

1. A toroidal two-cycle engine, comprising, a cylinder unit withcircumferentially spaced blocks having toroidal cylinder bores in commontoroidal alignment, said cylinder unit having enclosed scavengingchambers between said cylinder blocks, a pair of counterrotating shaftscoaxially mounted in said cylinder unit, a pair of opposed scavengingvanes fixed to one of said shafts and sliding in one opposite pair ofsaid scavenging chambers, a pair of opposed scavenging vanes fixed tothe other of said shafts and sliding in the other opposite pair of saidscavenging chambers, pistons secured on and extending from oppositesides of each of said scavenging vanes and sliding in said cylinderbores, each of said cylinder bores having inlet ports at one end andoutlet ports at the other end thereof, an intake manifold communicatingwith all of said inlet ports, each of said scavenging chambers having aninlet for connection to a source of combustible mixture, transfer portsfrom each of said scavenging chambers to said intake manifold, withnonreturn valve means therein, and synchronizing means interconnectingsaid shafts to rotate equally in opposite directions.
 2. An engineaccording to claim 1, wherein said transfer ports are at opposite endsof each of said scavenging chambers.
 3. An engine according to claim 1,wherein said pistons are in pairs secured in end to end abuttingrelation in said scavenging vanes.
 4. An engine according to claim 1,and including ignition means in each of said cylinder bores.
 5. Anengine according to claim 1, and including a separator plate fixed to atleast one of said cylinder unit and enclosing the ends of saidscavenging chambers, said transfer ports extending through saidseparator plate.
 6. An engine according to claim 5, wherein said valvemeans are mounted on said separator plate.
 7. An engine according toclaim 6, wherein said valve means comprises resilient reed valvessecured to said separator plate externally of the scavenging chambersand normally closing said transfer ports.
 8. An engine according toclaim 5, and including an end cover secured over said separator platesaid intake manifold comprising an annular channel in said end cover. 9.An engine according to claim 8, and including an annular exhaustmanifold in said end cover, communicating with said exhaust ports.